Digital rights management system, devices, and methods for binding content to an intelligent storage device

ABSTRACT

The present invention relates to digital rights management (DRM) for content that may be downloaded and bound to a storage device. The storage device may be an intelligent storage device, such as a disk drive, or network attached storage. In addition, the storage device is capable of performing cryptographic operations and providing a root of trust. In one embodiment, the DRM employs a binding key, a content key, and an access key. The binding key binds the content to a specific storage and is based on a key that is concealed on the storage. However, the binding key is not stored on the storage with the content. The content key is a key that has been assigned to the content, for example, by a trusted third party. The access key is determined based on a cryptographic combination of the content key and the binding key. In one embodiment, the content is encrypted based on the access key and stored in encrypted form in the storage device.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationNo. 61/622,312, filed Apr. 10, 2012 entitled, “DIGITAL RIGHTS MANAGEMENTSYSTEM, DEVICES, AND METHODS FOR DIGITAL CONTENT,” and is related toU.S. patent application Ser. No. 13/460,616, filed Apr. 30, 2012,entitled “DIGITAL RIGHTS MANAGEMENT SYSTEM AND DEVICES FOR ACCESSINGCONTENT FROM AN INTELLIGENT STORAGE,” and U.S. patent application Ser.No. 13/460,766 filed Apr. 30, 2012, entitled “DIGITAL RIGHTS MANAGEMENTSYSTEM AND METHODS FOR PROVISIONING CONTENT TO AN INTELLIGENT STORAGE,”all of which are herein incorporated by reference in their entirety.

BACKGROUND

Many different digital rights management (“DRM”) systems have beenproposed and implemented on various platforms. In general, DRM refers totechnologies that are used to control the use of digital content anddevices. For example, DRM is commonly used to prevent unauthorizedcopying of digital content.

Today, there exists a wide variety of computing devices that enableusers to copy and distribute digital content, especially content thathas been downloaded or stored on a storage device, such as a hard disk.Furthermore, most DRM systems to date have security weaknesses and havebeen circumvented. Unfortunately, due to these weaknesses of current DRMsystems, content companies have limited their offerings or have employedDRM systems that are difficult to use.

BRIEF DESCRIPTION OF THE DRAWINGS

Systems and methods which embody the various features of the inventionwill now be described with reference to the following drawings, inwhich:

FIG. 1 shows an exemplary system according to one embodiment;

FIG. 2 shows an exemplary audit system according to one embodiment;

FIG. 3 shows an exemplary download system according to one embodiment;

FIG. 4 shows an exemplary client system according to one embodiment;

FIG. 5 shows an exemplary storage device according to one embodiment;

FIG. 6 illustrates an exemplary process flow for generating a bindingkey that binds content to a storage device according to one embodiment;

FIG. 7 illustrates an exemplary process flow for provisioning content toa storage device according to one embodiment; and

FIG. 8 illustrates an exemplary process flow for playing contentaccording to one embodiment.

DETAILED DESCRIPTION

In one embodiment, digital content may be bound to a specific device.Digital rights management (“DRM”) methods and systems are provided forcontrolled distribution and playback of digital content. The digitalcontent may comprise the content itself plus metadata. The content maybe text, documents, audio, video, multimedia, video games, etc. in anyknown format. The content metadata may be any data or informationassociated with the content that is used for handling of the content.The content metadata may be employed to provide for secure handling ofthe digital content and to provide DRM protections. The content metadatamay also comprise one or more digital certificates.

For example, servers providing content may encrypt each copy of contentbased on an access key that is unique to that copy of the content. Thus,if an access key is compromised, the protection of only one copy of thecontent is compromised. In another embodiment, asymmetric cryptographymay be employed for securing content. In one embodiment, the contentthat is encrypted may only be a portion or portions of the text,document, audio, video, multimedia, etc.

In addition, the content may be uniquely bound to specific devices, suchas an intelligent storage device, based on the configuration of theaccess key. For example, the access key for the content is generatedfrom at least two components. The first component is a binding key thatis unique to the storage device on which the content is stored. In oneembodiment, the storage device may generate the binding key using arandom number and inputting the random number into a key generator. Thesecond component is a content key that is unique to the content. In oneembodiment, the algorithm for generating the access key may beimplemented as a licensable or renewable function.

In one embodiment, digital content may be securely accessed based on acryptographic key, such as a content key. In addition, in oneembodiment, only certain entities are provided the algorithm forgenerating the access key based on the two components. For example, thestorage device holding content does not retain any copies of its bindingkey nor does it have the algorithm for generating the access key. Thealgorithm for generating the binding key may be licensable andrenewable.

In one embodiment, two-way authentication is employed, for example,using public key infrastructure (“PKI”) and public key certificate-basedauthentication to ensure that entities in the system are trusted. Thevarious components of the system, such as a storage device, may beintelligent, and thus, capable of two-way authentication with eachother, which was not possible in the prior art. For example, the storagedevice and the player or download server may mutually authenticate witheach other. This form of authentication ensures that the storage deviceconfirms a trust relationship with the player and vice versa.Conventional DVD and Blu-ray discs did not contain such features toauthenticate or establish trust with a player or download server. ThePKI thus provides an environment in which entities of the DRM system canregister their identity and establish trust with each other.

In one embodiment, digital content may be provisioned and bound to aspecific device, such as a storage device. In one embodiment, theentities of the DRM system employ public key certificates, i.e., digitalcertificates for authentication of their identity and determineauthorization for various uses of their content. In another embodiment,a trusted party manages a certificate authority (“CA”) to supervise thePKI and digital certificates. In addition, multiple levels of CA's canbe accommodated in any of the embodiments.

All devices of the DRM system may be issued a certificate from one ormore of the CA's. If needed, one embodiment may provide for fullrevocation of a certificate for an entity. As noted, two-way mutualauthentication may be employed between entities to establish securecommunications channels for exchanging and distributing the content.Each item of content may also be issued a digital certificate. Thisallows the content to play a role in determining whether a device can betrusted.

Certain embodiments of the inventions will now be described. Theseembodiments are presented by way of example only, and are not intendedto limit the scope of the inventions. Indeed, the novel methods andsystems described herein may be embodied in a variety of other forms.Furthermore, various omissions, substitutions and changes in the form ofthe methods and systems described herein may be made without departingfrom the spirit of the inventions. To illustrate some of theembodiments, reference will now be made to the figures.

FIG. 1 shows an exemplary system 100 of the embodiments. As shown, thesystem 100 may comprise, among other things, an audit system 102, adownload system 104, a client system 106, and a network 108. Thesecomponents and certain aspects of their operation will now be furtherdescribed.

The audit system 102 serves as a trusted party for system 100. Inaddition, the audit system 102 may provide various management functionsrelated to the distribution and playback of content in system 100. Inone embodiment, the audit system 102 validates and certifies encryptionkeys as part of the PKI employed in system 100. The audit system 102 isfurther described with reference to FIG. 2.

The download system 104 comprises the hardware and software componentsfor distributing content in system 100. In one embodiment, the downloadsystem 104 comprises a website, which includes links to the content. Thedownload system 104 may also provide links to allow for transactionswith the audit system 102, such as links to key servers and certificateauthorities. The download system 104 is further described with referenceto FIG. 3.

The client system 106 may be any device used to access content providedby the system 100. For example, the client system 106 may comprise acomputer, a television, a portable or mobile device, a video gameconsole, a portable video game console, as well as associated storage.Any device capable of downloading, storing, or playing content may beimplemented as part of the client system 106. For example, the clientsystem 106 may comprise a desktop computer, a laptop computer, a tablet,a smartphone, a television, a digital video recorder, a set-top box, avideo game console, a portable video game console, or other form ofelectronic device. The client device 106 may also comprise a networkthat is wired and/or wireless and storage, such as a network attachedstorage (NAS) or external drives. The embodiments may work with any formof storage device, such as solid state and flash memory storage. Theclient system 106 is further described with reference to FIG. 4.

The network 108 provides a communication infrastructure by which thevarious components of system 100 communicate. Network 108 may compriseany collection of networks and network elements. For example, thenetwork 108 may be implemented over the Internet. However, the network108 may comprise any local area network, metropolitan area network, orwide area network and may be implemented as a private network, a publicnetwork, etc. Additionally, network 108 may comprise wired or wirelesscommunication links.

The system 100 may support several scenarios for downloading and playingcontent. For example, content can be downloaded via the network 108 to aportable storage device from client system 106. The content may then beplayed on a playback device, such as a Blu-Ray player, game console, TV,by streaming the content from the storage device. As another example,the playback device may include an integrated storage device that isused for both download and playback of content. As another use case,content may be downloaded onto a NAS system in client system 106.

Yet another implementation may comprise a client system 106 having amedia player or storage device to which the content is bound. A user ofclient system 106 may then remotely access the content and play it on amobile device, such as an iPad, iPod, iPhone, a portable video gameconsole, such as PlayStation® portable or a Nintendo DS, etc., which isconnected to the media player or storage device via a secure connection,such as a wireless connection, over a WiFi, 3G, 4G, or othercommunication channel. In another implementation of system 100, theclient system 106 comprises a portable media player or storage devicethat is accessible wirelessly, such as via Bluetooth or WiFi or similarcommunication system. The portable media player or storage device inclient system 106 may thus act as a source of content for playback onportable and network enabled viewing devices in client system 106.

FIG. 2 shows an exemplary audit system of the embodiments. As shown, theaudit system 102 may comprise a key server 200, a key database 202, anda certificate authority 204.

The key server 200 is a server that receives and serves variouscryptographic keys used in one embodiment. The key server 200 may beimplemented using known hardware and software. In one embodiment, thekey server 200 distributes keys as part of a digital certificate. Thedigital certificate may contain the key and also information about theowner of the key. The key server 200 may provide certificates in a knownformat, such as X.509, PKCS, Open PGP, etc.

The key database 202 stores the keys and other related information usedby the key server 200. The key database 202 may be implemented usingwell-known database management systems, such as Oracle, DB2, MicrosoftSQL, PostgreSQL, and MySQL.

The certificate authority (or CA) 204 issues digital certificates forthe system 100. Certificate format and contents may be customized foreach trusted party in system 100. In addition, in one embodiment, eachitem of content may have a trusted party certificate as part of itsmetadata. The certificates allow software associated with the content toindependently determine if a player in client system 106 is attemptingto access the content can be trusted. For example, software associatedwith the content could restrict high definition content or otherportions of content from being accessible to a player, if the player inclient system 106 is not trusted. In system 100, any trusted party canrevoke all certificates, revoke certain certificates, or certainportions of certificates that have been issued

In one embodiment, public key infrastructure (“PKI”) is used forcertificate signing. For example, in system 100, PKI is used in clientsystem 106 during device authentication and to establish a securecommunications channel between a storage device, download system 104, orplayback device. In one embodiment, two-way authentication is employedbetween the various entities in system 100. For example, the storagedevice may be an intelligent device that is configured to activelyauthenticate and establish a trust relation with a playback device ordownload server 104 based on two-way authentication.

Between entities of system 100, each secure session may use uniquesecurity parameters. For example, the session key, session ID,initialization vector (“IV”), hash-based message authentication code(“HMAC”) key may be made unique for each session. In one embodiment, thesystem 100 uses secure channels of communication that are protectedbased on symmetric cryptography. In another embodiment, the system 100may use PKI to establish secure channels.

FIG. 3 shows an exemplary download system of the embodiments. As shown,the download system 104 may comprise a download server 300 and a contentdatabase 302.

The download server 300 delivers the content for the system 100, forexample, to client system 106. In one embodiment, download server 30encrypts the content with an access key that may be derived from abinding key and a content key. The binding key and content key arefurther described below.

As shown, the download server 300 may comprise a web server thatprovides various web pages 306 to client system 106 to make content incontent database 302 accessible. In one embodiment, the download server200 provides one or more websites having a collection of web pages 306in order to serve the content.

In one embodiment, each copy of content is uniquely encrypted. Thecontent may be uniquely encrypted in its entirety or certain portions ofthe content may be uniquely encrypted. Thus, if an item of content orits access encryption is ever compromised, the compromise is limited tothat item of content. As will be described further below, only thedownload server 300 and a player have the algorithm to generate theaccess key. In addition, as noted, the algorithm for generating theaccess key may be licensable or a renewable function.

The content database 302 stores the content, content metadata, andrelated information served by the download server. Provides a storageand access infrastructure for providing the items of content. Suchdatabase management systems are known to those skilled in the art.

The content providers 304 conceptually represent the source of thecontent. For example, the content providers 304 may represent otherdatabases or content repositories, content delivery networks, and thelike. Any source of content may be included in any of the embodiments.

FIG. 4 shows an exemplary client system 106 of the embodiments. Aconcern of many content providers is software-based players in clientsystems are considered a high security risk due to their ease ofmodification and susceptibility to hacking. One benefit of theembodiments is that client system 106 includes devices having a hardwareroot of trust. A hardware root of trust in a device comprises securecryptographic hardware that enables playback of the content that is notjust software based, but instead makes use of the cryptographic hardwareprovided in the hardware root of trust.

For example, in one embodiment, media players may include dedicatedhardware cryptographic processing circuits and cryptographic boundariesfor performing secure computations and secure storage of criticalcryptographic parameters. As another example, network attached storage(“NAS”) controllers may include dedicated hardware that can serve as aroot of trust. Accordingly, one embodiment may provide a secure DRMsystem enabling secure download of content, secure storage of content,and secure playback of content.

As will be further described, the client system 106 comprises anintelligent storage device 402 having a controller 408 that includes ahardware root of trust as part of a cryptographic processing module 409.In the embodiments, the cryptographic processing module 409 is isolatedfrom the other controller functionality. Clear text asymmetric andsymmetric key access is limited to the cryptographic module 409. In thisembodiment, asymmetric and symmetric keys may be generated within thecryptographic module 409. Public/private key pairs are used with the DRMof system 100. Any keys stored outside the cryptographic module 409 arecryptographically protected. Since the asymmetric and symmetric keys areinside the cryptographic module 409, it is difficult for an attacker togain access to the private keys. This allows for a secure PKIimplementation as part of the DRM of system 100. In another embodiment,various keys or encryption data may be injected or securely stored onthe storage device 402. For example, one or more keys may be injected onto the storage device 402 in a secure manufacturing environment.

In one embodiment, the cryptographic module 409 is used to generateadditional keys securely inside its boundaries. For example, thecryptographic module 409 may be configured to generate a binding keythat is used to bind content to the storage device 402. Thecryptographic module 409 may also include a capability to digitally signsecure information and store it in non-secure memory, and digitally signand encrypt secure information and store it in non-secure memory.

In one embodiment, playback devices in client system 106, such as hostdevice 400, may also be issued certificates from a certificate authority204. The host device 400 may be, for example, a computer, a television,a portable or mobile device, a video game console, a portable video gameconsole. This certificate may be stored in a secure area not accessibleby the processor of the player in one embodiment. In another embodiment,the player running, for example, on a host device 400 may store thecertificate anywhere, such as, in a user area of the storage device 402or other non-secure area. The playback device may store the certificatein encrypted form or protected form, such as with a digital signature.When the player and storage device 402 perform authentication, thecryptographic modules in both devices will be the only entities thathave access to the secure data to perform authentication and toestablish a secure communication channel.

However, in one embodiment, the content and content metadata does notprovide the access key for accessing the content. Instead, once a securecommunication channel is established, the playback device (such as hostdevice 400) will request the binding and content key from the storagedevice 402. Responsive to this request, the storage device 402 may thensend the binding and content keys to the player so that it can generatethe access key. The access key is used to decrypt and render thecontent. Those skilled in the art will recognize that by using thesesecure cryptographic modules for security related communications andhandling of security parameters, and content metadata (such as thebinding and content keys), the DRM of system 100 is more difficult toattack and compromise than existing systems.

As shown, the host device 400 may comprise, among other things, aprocessor 404, a host cryptographic module 405, and an output device406. These components of host device 400 will now be further described.

The processor 404 comprises the hardware for executing instructionsdirecting the operations of the host device 400. Such processors areknown to those skilled in the art.

The host cryptographic module 405 comprises the hardware for carryingout cryptographic operations for the host device. In addition, the hostcryptographic module 405 may be packaged or embedded with varioussecurity measures to resist tampering.

The output device 406 represents any device intended to output content.For example, the output device 406 may comprise a display, audiospeakers, etc. Such output devices are well known to those skilled inthe art.

The storage device 402 may comprise, among other things, a controller408, a cryptographic module 409, and a storage media 410. Thesecomponents of storage device 402 will now be further described.

The controller 408 comprises the hardware and firmware that controls theoperation of the storage device 402 and enables communications with thehost device 400. Controller 408 may be implemented using known hardwareand components.

The cryptographic module 409 provides a basis of trust, such as ahardware root of trust, for the storage device 402. In one embodiment,the cryptographic module 409 is a secure crypto-processor that isconfigured to perform various cryptographic operations. In oneembodiment, cryptographic module 409 may be implemented as an externalsystem on chip that is packaged with various security measures to maketamper resistant or detection. In another embodiment, a cryptographicmodule 409 may be implemented as part of or embedded within anothersystem-on-chip or other hardware that is packaged with various securitymeasures to detect tampering and make it tamper resistant. Thecryptographic module 409 may or may not be isolated from the othersystem-on-chip (“SoC”) functions,

The storage media 410 refers to the physical media used by the storagedevice 402 to store information. In one embodiment, the storage media410 may comprise magnetic media, optical media, semiconductor media,such as flash memory, and the like. The storage media 410 may compriseany combination of these media in one embodiment.

FIG. 5 further shows an exemplary storage device 402 of the embodiments.As shown, the cryptographic module 409 may comprise a secured memory502. In addition, the storage media 410 may comprise a user area 504 anda non-user area 506.

The secured memory 502 provides a secure area to store sensitiveinformation, such as content metadata, related to the DRM provided bysystem 100. In one embodiment, the secured memory 502 is implemented asa one-time programmable non-volatile memory (“OTP NVM”). As an OTP NVM,the secured memory 502 can only be programmed once and is difficult toalter. In addition, the secured memory 502 may also comprise one or morememories, such as a ROM, static RAM, and dynamic RAM.

As to user area 504, this area of storage media 410 is provided asstorage space that is accessible by the host device 400. For example,the user area 504 may be addressable based on logical block addresses(“LBA”) used by the host device 400.

The storage device 402 can be configured to contain a partition in theuser space 504 that is secured. That is, data in this partition may beencrypted using a separate key generated by the cryptographic module409. Access to this partition would only granted to authenticateddownload clients or players (such as players running on host system400). In one embodiment, all or certain data from this partition in userspace 504 may only be sent over a secure authenticated channel.

This partition of user space 504 can be used, for example, foradditional content metadata files and information related to the DRM ofsystem 100. The actual content itself may be sent from the downloadserver 300 or to a player in client system 106 only in encrypted form,so the content can be stored in the user space 504.

As shown, the storage device 402 may also comprise a non-user area 506.The non-user area 506 is a reserved area of the storage media 410 thatis not directly accessible by the host 400. For example, the non-userarea 506 may refer to an area that is not addressable by the host system400. In one embodiment, the non-user area 506 is reserved for use by thecontroller 408 and cryptographic module 409, for example, to storevarious sensitive information, such as content metadata information,related to the DRM of system 100.

In one embodiment, the cryptographic module 409 may create new securekeys and allow the storage device 402 to create a secure unique diskencryption key for a special partition area of the medium that is notvisible in the user LBA space, such as the non-user area 506. Thecryptographic module 409 using this key may thus encrypt all datawritten to this non-user area 506.

The non-user area 506 may be used to store secure metadata related tothe DRM of system 100. This metadata may include, for example,certificates, key files, license files, etc. For example, the storagedevice 402 may have a certificate issued to it from certificateauthority 204. This certificate may be stored in this non-user area 506and will be encrypted with the key for this area. This will bind thecertificate to the storage device 402. Thus, if a clone copy of thedrive is somehow fabricated, the clone will not include the encryptionkey used for the non-user area 506, and thus, the data stored in thisarea cannot be correctly decrypted. Alternatively, critical securityparameters, such as keys, certificates, or other objects, may beindividually cryptographically protected and stored to the storagemedia.

Accordingly, in one embodiment, in order to access content, thecontroller 408 and the recording medium 410 cannot function separatelyfrom each other. In other words, a complete copy of either thecontroller 408 or the medium 410 individually will not be sufficient toaccess content.

FIG. 6 illustrates an exemplary process flow for generating a bindingkey that binds content to a storage device. In one embodiment, thestorage device 402 may generate the binding key using a random numberand inputting the random number into a key generator. The key generatormay be software running in storage device 402 or a hardware component ofstorage device 402. In one embodiment, the binding key is made from twoparts. In one embodiment, the first part is based on the defect list ofthe storage device. The second part is based on a key concealed by acryptographic module on the storage device. In order to protect thebinding key, the binding key is not stored with the content or with thecontent metadata in the storage device 402. Instead, the parts of thebinding key are stored separately. In addition, in one embodiment, thebinding key is generated as an ephemeral key, and thus, computed by thestorage device 402 only when needed. This method also includes thecapability for renewable functions. As noted, the binding key may beunique to individual storage devices or unique to a class of devices,such as devices of the same type, etc.

As shown, first, the storage device 402 is prompted to determine oridentify a unique characteristic about itself. For example, the storagedevice 402 may determine or identify a defect list 600. In oneembodiment, the defect list 600 corresponds to the P-list or time-zerolist of defects that were present on storage media 410 at the time ofmanufacture. Of course, in other embodiments, the unique characteristicmay be derived or originate from other portions of the storage device402.

Second, the cryptographic module 409 cryptographically processes thedefect list 600 and generates a unique identifier 602. For example, thecryptographic module 409 may calculate a hash of information from thedefect list 600. In addition, the cryptographic module 409 may digitallysign the unique identifier 602. Alternatively, the unique identifier maybe generated by using a random number generator to generate a randomnumber that is unique to the storage device. For example, thecryptographic module 409 may comprise a random number generator that isa physical device or component within cryptographic module 409 orsoftware running in the cryptographic module 409. Alternatively, therandom number generator may be separate software or a hardware devicerunning on the storage device 402.

Third, the cryptographic module 409 may store the unique identifier 602in a secure area. For example, as shown, the cryptographic module 409may also store the cryptographically protected unique identifier 602 inthe non-user area 506.

Fourth, the cryptographic module 409 may generate a concealed key 604.In one embodiment, the key 604 is concealed in that it is not storedwith the other content metadata and instead resides in the securedmemory 502. The cryptographic module 409 may generate one or a set ofmultiple concealed keys 604. Thus, if one of these keys becomescompromised, the cryptographic module 409 may switch to the next key inthe set. If all the keys are used, or if it is not desired to create andstore a set of keys, then the cryptographic module 409 may generate anew concealed key 604 upon request. Of note, the controller 408 may beconfigured to track which content is bound to which key.

Based on the unique identifier 602 and the concealed key 604, thestorage device 402 may generate a binding key 606 that is derived frominformation provided by both the controller 408 and from uniquecharacteristics of the storage medium 410. In one embodiment, thecryptographic module 409 ephemerally generates the binding key 606.

The binding key 606 cryptographically binds content to the storagedevice 402. For example, the binding key 606 may be sent as part of thecontent's metadata over a secure communications channel to the downloadserver 300 in download system 104. The download server 300 may then usethe binding key 606 as one component of an access key used to encryptthe content.

At appropriate times, the binding key 606 may also be made available toauthenticated players over a secure channel for use during playback ofthe content. For example, the storage device 402 may be configured witha special command that is only accepted when the sending device has beenauthenticated and is communicating over a secure channel.

Based on the binding key 606, even if an exact bit-by-bit copy of theentire media 410 is accomplished, the cloned media will not be usablefor rendering the content since the concealed key in storage deviceunique and securely stored in the secured memory 502 of thecryptographic module 409 and is not copy-able or clone-able to anotherdrive.

FIG. 7 illustrates an exemplary process flow for provisioning content toa storage device. In this embodiment, revocability and renewability areattributes of the DRM system. As an additional security systemcomponent, the process flow illustrated may comprise variousrenewability features. For example, keys may be retired or random keyspre-generated can be used with a secure allocation algorithm that caneither be varied from time to time or which makes use of multiple keysin a random fashion for each item of content to be provisioned to thestorage device 402. For example, the embodiments may utilize tokenizingof an update file that could be suitable for all players.

In one embodiment, the process relates to provisioning of content andcontent metadata, such as a binding key and content key. Other metadata,such as digital certificates, etc., may also be provisioned as part ofan embodiment.

As shown, first, the storage device 402 and the download server 300establish a secure communication channel with each other. For example,the download server 300 and the storage device 402 may employ PKI toestablish a secure communications channel. In particular, the host 400may request a certificate from the storage device 402. The storagedevice 402 may retrieve its certificate, for example, from its non-userarea 506 in media 510. The storage device 402 may then send a devicesession ID and its certificate. The certificate includes its public key;Public_(Device).

In one embodiment, host 400 (not shown in FIG. 7) verifies thecertificate. For example, the host 400 may check the signature on thecertificate. Host 400 may also checks its revocation list to make surethe certificate from storage device 402 is not revoked. Alternatively,host 400 may communicate over network 108 with audit system 102 andcertificate authority 204 to verify the certificate and check revocationstatus of the certificate.

Host 400 then responds by sending a host session ID and its certificate,which includes its public key, Public_(Host), to storage device 402. Thestorage device 402 verifies the host certificate and checks thesignature. The storage device 402 may also check its own revocation listto make sure the host 400 is not revoked.

Next, the host 400 may request a session key from the storage device402. In response, in one embodiment, the storage device 402 encrypts arandom session key, a random device initialization vector (“IV”), andrandom device hash-based message authentication code (“HMAC”) key withPublic_(Host), and sends it to host 400.

Host 400 decrypts the information with Private_(Host) to recover thedevice session key, the device IV, and the device HMAC key. Host 400encrypts a random host session key, a random host IV, and random hostHMAC key with Public_(Device), and sends this information to storagedevice 402. The storage device 402 then decrypts this information withPrivate_(Device), to recover the host's 400 session key, host IV, andhost HMAC key.

The host 400 may also encrypt a random challenge with the device sessionkey and sends it to the storage device 402. The storage device 402decrypts the host random challenge with the device session key, and thenencrypts the host random challenge with the host session key, and sendsthis information back to the host 400. The host 400 decrypts the hostrandom challenge with the host session key and confirms it matches whatwas originally sent to the storage device 402. This proves the storagedevice 402 knows the private key that corresponds to the public key thatwas sent with its device certificate.

For further confirmation, the host 400 may request a random challengefrom the storage device 402. The storage device 402 encrypts a devicerandom challenge with the host session key and sends this information tothe host 400. The host 400 then decrypts the device random challengewith the host session key and encrypts the device random challenge withthe device session key and sends this information back to the storagedevice 402. The storage device decrypts the device random challenge withthe device session key and confirms it matches what was originally sentto the host 400. This proves the host 400 thus knows the private keythat corresponds to the public key that was sent with the host's 400certificate

In one embodiment, the storage device 402 may use AES encryption withthe host session key and host IV for secure messages to the host 400.The host 400 also uses AES encryption with a device session key anddevice IV for secure messages to the storage device 402.

Once the secure session has been established, session communications maybe carried out using asymmetric or symmetric algorithms. In oneembodiment, each secure message may include a header with a sequencenumber and message length, a body message AES encrypted with appropriatesession key and IV, and a footer having a SHA-256 HMAC of message body.In another embodiment, session communications are established based onasymmetric encryption and then secured based on symmetric encryption.For example, once the secure session has been established, sessioncommunications may be carried out based on symmetric encryption, such asAES encryption and AES decryption with the session keys and IV'sestablished. Each secure message may include a header with a sequencenumber and message length, a body message AES encrypted with appropriatesession key and IV, and a footer having a SHA-256 HMAC of message body.In another embodiment, asymmetric encryption may be employed to securetraffic during the session, as well.

Second, now that secure channel has been established, the downloadserver 300 requests the binding key from the storage device 402. Inparticular, the download server 300 may send a message via the securechannel to the storage device 402. As noted, in one embodiment, thebinding key 606 is initially absent from the content's metadata and isgenerated when needed.

Third, the storage device 402 generates the binding key 606. Inparticular, the cryptographic module 409 generates the binding key 606based on the unique key 602 and the concealed key 604.

In one embodiment, the cryptographic module 409 employs a one-way hashalgorithm or an Advance Encryption Standard (AES) algorithm to generatethe binding key, Kb, where:Kb=F(Kroot,IDm)

Where F is a one-way function,

Kroot is a key generated by the cryptographic module 409, i.e., theconcealed key 604,

IDm is a unique media identifier number assigned during manufacture ofthe storage device 402, such as unique identifier 602.

Alternatively, the cryptographic module 409 may generate the binding keyusing a random number, such as from a random number generator, andinputting this random number into a key generator. The key generator maybe software or a hardware component in the cryptographic module 409.

Fourth, the download server 300 requests from the key server 200 acontent key for protecting the content. The content key may be assignedto the content in various ways. For example, the key server 200 mayassign a content key 700 that is unique to each item of content. In oneembodiment, the content key 700 is provided as part of the content'smetadata and stored on the storage device 402. The content key 700 maybe cryptographically protected when sent to the host 400.

Fifth, the key server 200 provides the content key 700 to the downloadserver 300. In particular, the key server 200 may establish a securechannel with the download server 300, for example, based on PKI.

Sixth, the download server 300 generates an access key 706 based on thebinding key 606 and the content key 700. In particular, the downloadserver 300 may employ a unique algorithm to cryptographically combinethe binding key 606 and content key 700 and generate the access key 706,for example, based on a one-way hash algorithm. The unique algorithm maybe known only to certain entities of the system 100, such as thedownload server 300 and trusted playback devices in client system 106.The algorithm may be a licensable or renewable function. In addition,one or more algorithms may be passed from the download server 300 totrusted components in client system 106 via a field or portion in thesecure metadata of the content. For example, a set of multiplealgorithms may be initially configured or established within trustedcomponents of client system 106. The download server 300 may thenprovide a pointer or indicator in a content's secure metadata which ofthe set algorithms to employ when generating the access key

In one embodiment, the access key 706 is not included in the contentmetadata nor is it stored on download server 300. For example, instead,the download server 300 may be configured to ephemerally generate theaccess key 706. Alternatively, information for generating the access key706 may be archived to a secure remote storage by the download server300. For example, the audit system 102 may serve as a secure repositoryfor securely storing the binding key 606 and/or the content key 700.

Seventh, the download server 300 provides the content key 700 to thestorage device 402. The storage device 402 then securely stores thecontent key 700. For example, the storage device 402 may store thecontent key 700 in the non-user area 506.

Eighth, the download server 300 encrypts all or portions of the content702 into encrypted content 704. For example, the download server 300 mayemploy AES encryption to encrypt the content 702 based on the access key706.

Ninth, the download server 300 provides the encrypted content 704 to thestorage device 402. The storage device 402 may then store the encryptedcontent 704, for example, in its user area 504.

FIG. 8 illustrates an exemplary process flow for playing content. Asshown, first, the host system 400 and the storage device 402 mayestablish a secure communication channel with each other. For purposesof brevity, an example of the establishment of a secure channel based onPKI was provided above with reference to FIG. 7. In one embodiment, thestorage device 402 will evaluate content's digital certificate and theplayer certificate to determine eligibility of the player to receive thecontent and/or content metadata

Second, the host system 400 requests the binding key 606 from thestorage device 402 because it is absent from the content metadata. Ofnote, in one embodiment, the storage device 402 does not retain thebinding key 606. In another embodiment, the host system 400 requests forthe binding key 606 are specific to the content to be played. If needed,this feature allows, for example, the storage device 402 to employdifferent algorithms for generating the binding key 606. The algorithmsused may depend on various criteria, such as the specific item ofcontent, the type of content, source of the content, number of copies ofthe content, for recovery, theft detection, etc.

Accordingly, third, the storage device 402 ephemerally generates thebinding key 606. In particular, as noted above, cryptographic module 409generates the binding key 606 based on a cryptographic combination ofthe concealed key 604 and the unique identifier 602. Once generated, thestorage device 402 may transmit the binding key 606 to the host system400.

Fourth, the host system 400 requests the content key 700 from thestorage device 402. In one embodiment, the content key 700 may beretrieved from the content metadata stored in non-user area 506 onstorage device 402. The host system 400 may request the content key 700based on a variety of parameters, such as a content identifier, and thelike.

Fifth, the storage device 402 provides the content key 700 to the hostsystem 400. For example, the storage device 402 may access the non-userarea 506 and transmit the content key 700 to the host system 400. Whenretrieving the content key 700, the cryptographic module 409 may need toperform various cryptographic functions, such as decryption, checking ofdigital signatures, etc.

Sixth, the host system 400 generates the access key 706 in order todecrypt the content. In particular, the host's cryptographic module 405generates the access key 706 based on a cryptographic combination of thebinding key 606 and the content key 700. The cryptographic module 405may be programmed with the unique algorithm that is known only withinthe cryptographic module 405 of the host system 400. For example, thecryptographic module 405 may comprise an OTP NVM that is programmed withthe algorithm for generating the access key 706. This feature allows,among other things, the access key 706 to be substantially absent fromthe content metadata.

Seventh, the storage device 402 provides the encrypted content 704 tothe host system 400. In one embodiment, the storage device 402 streamsthe encrypted content 704 to the host system 400.

Eighth, the host system 400 cryptographically processes the encryptedcontent 704 to recover the content 702 in unencrypted form. As noted, inone embodiment, content is encrypted based on symmetric cryptography,such as AES 128, using the access key 706. Once in decoded orunencrypted form, the host system 400 may then output the content 702 toan output 406. Of note, the host system 400 may re-encrypt the contentfor delivery to the output 406. For example, if the output 406 is a highdefinition multimedia interface (“HDMI”) device, then host 400 mayre-encrypt the content using High-bandwidth Digital Content Protection(“HDCP”) encryption currently specified for HDMI devices and transmitthe content in this secure form. In one embodiment, the host 400 maydecrypt the content and then re-encrypt the content using a securetransport encryption protocol, such as high bandwidth content protocol(HDCP), and outputting the re-encrypted content to a display device,such as TV, a monitor, etc. In another embodiment, the host 400 decryptsthe content, then re-encrypts the content using, for example, digitaltransmission content protection (DTCP), and sends the re-encryptedcontent to a playback device, such as a TV, a monitor, etc. Accordingly,in one embodiment, the content may always be in a secured form when intransit between entities of the system 100.

The features and attributes of the specific embodiments disclosed abovemay be combined in different ways to form additional embodiments, all ofwhich fall within the scope of the present disclosure. For example, inthe case of Network Attached Storage (“NAS”), the NAS storage maycontain one or more storage devices and implement various technologies(like RAID), which result in content that may be spread across multiplestorage devices. In the case of a NAS comprising a single drive, the NAScontroller may be configured to bind the content to the storage deviceof the single drive in similar fashion described above. In the case of aNAS comprising multiple drives, the content may be bound to the NASsubsystem instead of or in addition to a specific storage device orstorage medium. Accordingly, the NAS subsystem may contain a securecryptographic module. In this variation of the embodiments, for a NASstorage, a unique set of keys may be generated by the NAS controller andsecurely stored in the secure storage of the NAS. Then, content bindingto the NAS may be performed in similar fashion as described above. Thus,even if a clone copy of a drive is accomplished, this drive will not beusable unless it is installed into exactly the same NAS system. Thismethod may be useful in enabling replacement of a damaged drive in a NASRAID system, while ensuring that a cloned drive is not useful.

Although the present disclosure provides certain embodiments andapplications, other embodiments that are apparent to those of ordinaryskill in the art, including embodiments, which do not provide all of thefeatures and advantages set forth herein, are also within the scope ofthis disclosure. Accordingly, the scope of the present disclosure isintended to be defined only by reference to the appended claims.

What is claimed is:
 1. A storage device configured to generate a bindingkey for binding data stored in the storage device, said storage devicecomprising: a storage medium comprising a user area and a non-user area;and a controller comprising a cryptographic module providing a securedmemory separate from the storage medium, wherein the controller isconfigured to: generate a unique identifier based on defect dataassociated with the storage medium, the unique identifier being uniquelyassociated with the storage medium; store the unique identifier in thenon-user area of the storage medium; determine a first cryptographic keystored in the secured memory of the cryptographic module; generate abinding key that binds content to the storage device based at least inpart on the unique identifier and the first cryptographic key; providethe binding key to a remote download server over a secure communicationchannel; and receive content from the download server encrypted based inpart on the binding key.
 2. The storage device of claim 1, wherein thesecured memory comprises a one-time-programmable, non-volatile memory.3. The storage device of claim 1, wherein the controller is furtherconfigured to digitally sign the unique identifier based on informationprovided by a hardware root of trust of the cryptographic module.
 4. Thestorage device of claim 1, wherein the controller is configured togenerate the binding key as an ephemeral key.
 5. The storage device ofclaim 1, wherein the controller is further configured to prevent storageof the binding key in the user area of the storage medium.
 6. A digitalrights management system, said system comprising: a content key serverconfigured to provide a first cryptographic key for encrypting content;a storage device comprising a storage medium and a controller configuredto generate a binding key based on defect data associated with thestorage medium and the first cryptographic key; a download serverconfigured to: provide encrypted content to the storage device; receivethe binding key from the storage device; receive the first cryptographickey from the content key server; and encrypt the content based on atleast the first cryptographic key and the binding key; and a mediaplayer configured to receive the binding key, the first cryptographickey, and the encrypted content from the storage device, and decrypt theencrypted content based on at least the first cryptographic key and thebinding key.
 7. The system of claim 6, wherein the media player and thestorage device are configured to perform mutual authentication with eachother.
 8. The system of claim 6, wherein the media player is configuredto generate a decryption key based on at least the first cryptographickey and the binding key.
 9. The system of claim 6, wherein the storagedevice is configured as a network attached storage.
 10. The system ofclaim 6, wherein the storage device is configured to receive a privatekey and a public key in a secure manufacturing environment.
 11. A methodof determining a key that binds data to a storage device, wherein saidstorage device comprises a controller, a cryptographic module with amemory, and a storage medium, said method comprising: generating aunique identifier based on defect data associated with the storagedevice, the unique identifier being uniquely associated with a storagemedium of the storage device; store the unique identifier in a non-userarea of the storage medium; determining, by the cryptographic module, afirst cryptographic key that is concealed in the storage device;generating, by the cryptographic module, a binding key that bindscontent to the storage device based at least in part on the uniqueidentifier and the concealed first cryptographic key; and transmittingthe binding key to a server that provides the data to the storagedevice.
 12. The method of claim 11, further comprising determining thedefect data at least in part by identifying a set of defects present onthe storage medium.
 13. The method of claim 11, further comprisingdetermining the defect data at least in part by identifying a defect logon the storage medium that was generated when the storage device wasmanufactured.
 14. The method of claim 11, wherein generating the bindingkey comprises generating the binding key based on information in adefect log.
 15. The method of claim 11, further comprising digitallysigning the unique identifier based on information from a hardware rootof trust provided by the storage device.
 16. The method of claim 11,further comprising concealing the first cryptographic key in a securedmemory accessible by the cryptographic module.
 17. The method of claim11, wherein generating the binding key comprises: digitally signing theunique identifier based on information from a hardware root of trustprovided by the storage device; accessing the concealed firstcryptographic key; and determining the binding key based on at least thedigitally signed unique identifier and the concealed first cryptographickey.